The leader of Nigerian militant Islamist group Boko Haram is dead, according to reports. News agency Reuters said it had heard an audio recording made by Boko Haram's rivals The Islamic State West African Province (ISWAP), which said Abubakar Shekau died around 18 May. He died after detonating an explosive device, according to a person on the recording who identified himself as ISWAP leader Abu Musab al Barnawi. Al Barnawi said his fighters had sought the warlord on orders of Islamic State leadership, chasing him and offering him the chance to repent and join them. "Shekau preferred to be humiliated...